Compound hydrostatic transmission

ABSTRACT

A compound hydrostatic transmission wherein a speed increaser transmission is added to a steering transmission, the steering transmission including end planetaries whose sun gears are driven by one source from the speed increaser transmission and whose ring gears are capable of being braked or being driven by another source from the speed increaser transmission in producing low speeds with heavy torque and high speeds with lower torques, respectively, the steering transmission, in between the end planetaries, having infinitely variable hydrostatic means and being capable of driving the end planetaries at the same speeds or at different speeds in a steering operation departing from the straight-away.

United States Patent Cockrell et al. 5] Mar. 21, 1972 541 COMPOUNDHYDROSTATIC 3,575,066 4/1971 Livezey et al "74/7205 TRANSMISSION PrimaryExaminer-Arthur T. McKeon [72] Inventors: 'g g Attomey-Frank L.Neuhauser, Oscar B. Waddell, Joseph B.

o n organ nora Forman, Carl W. Baker and Francis K. Richwine [73]Assignee: General Electric Company [22] Filed: Sept. 25, 1970 [57]ABSTRACT A compound hydrostatictransmission wherein a speed in- [211Appl' 75554 creaser transmission is added to a steering transmission,the steering transmission including end planetaries whose sun 74/752 C,7 gears are driven by one source from the speed increaser trans- Int ClF161! H61! 860k 21/00 mission and whose ring gears are capable of beingbraked or of Search being driven another ource from the speed increasetrans. mission in producing low speeds with heavy torque and high [56]References cued speeds with lower torques, respectively, the steeringtransmis- UNITED STATES PATENTS sion, in between the end planetaries,having infinitely variable hydrostatic means and being capable of dnvmgthe end 9 1/1952 f y et planetaries at the same speeds or at differentspeeds in a steerl LewlS v ing operation from the straight.away3,492,89l 2/1970 Livezey.... .....74/720.5 3,545,303 12/1970 Whelahan..74/720.5 15 Claims, 3 Drawing Figures PAIENTEDMAR 21 I972 SHEET 1 [1F3 INVENTORS SANFORDC.COCKRELL ROBERT J.DORGAN BY I Q THEIR ATTORNEYPATENIEDMARZI I972 3,650,159

SHEET 2 UF 3 3/ 6 J l2 5 I 8 l FIG. 2

INVENTORS THEIR ATTORNEY COMPOUND HYDROSTATIC TRANSMISSION BACKGROUND OFTHE INVENTION A tractor type vehicle has continuous treads or tracks oneach side of the vehicle which are driven at uniform speeds that drivesthe vehicle in a straight path, but are driven at different speeds whenit is desired to turn the vehicle, the vehicle turning around the lowspeed side. When an extremely high degree of movability for the vehicleis desired, the transmission must produce infinitely variable speedsalong the straightaway and, in the turning operation, the speeds must beinfinitely variable and differentially applied. In such vehicles, thiscapability must be accompanied by the proper torque and speedrequirement commensurate with the load and the transmission producingthe variable speed should be carried out with a continuous drive appliedto the load. This requirement is not accomplished by the use of gearshifting-type transmission and the use of clutches in the transmissionbecause such type of transmission interrupts the drive power to the loadduring the shifting operation. In extremely heavy vehicles, suchinterruption creates a rough operation of the vehicle and can causeextreme wear and tear on the transmission and other parts of thevehicle.

Other types of transmissions attempt to avoid the disadvantages of gearshifting by the use of hydrostatic controlled planetary gearing. Thesetype of transmissions do not develop the proper torque multiplicationand extreme speed range for satisfactorily controlling such vehicles.

SUMMARY OF THE INVENTION It is the object of this invention therefore toprovide a transmission that will create greater torque multiplicationand provide a greater range of variable speed without creating pause inits application to the load. This is accomplished by adding a speedincreaser transmission to a steering transmission and controlling theincreaser transmission to provide dual drives to the steeringtransmission.

The speed increaser transmission has an input that is directed to ashaft that drives the cylinder block of its pump and also the sun gearof a planetary gearing wherein the hydraulic fluid of the pump istransmitted to a fluid motor that drives the ring gear of the planetarygearing, the pump having capabilities of varying the amount of fluidfrom the pump and in this way varying the speed of the motor and theconnected ring gear of the planetary gearing to control the variationsof speed to the planet gear support of each planetary gearing. Thesteering transmission is also provided with a gear fixed to the inputdrive shaft, a gear connected to the support of the planet gears and abrake applied to the gear and planet support combination.

A steering transmission has a center shaft driven by the gear affixed tothe power input shaft of the steering transmission, which center shaftdrives a left and a right hydraulic pump unit and a right and a left sungear of a right and left planetary gearing. The right and left motorunit drives the ring gears of the right and left planetary gearing inthe same manner previously described. Second right and left planetarygearing having their sun gears driven by the planet gears of the rightand left planetary gearing first mentioned, and a planet gear support ofthe second mentioned planetary are connected to the right and leftoutput shaft, respectively. The gear affixed to the planet gear supportof the speed increaser transmission drives a gear affixed to a shaftthat extends across the steering transmission to drive the ring gears ofthe second planetary gearing for a high speed drive or to hold the ringgears stationary when it is desired to provide a low speed drive. Thethree sets of pump-motor units can drive their associated ring gears ineither forward or reverse direction with a considerable variance inspeed or torque and this coupled with the direct and planetary drive tothe steering transmission creates an even greater variance in the speedand torque of the transmission as a whole, inasmuch as the planetarydrive from the speed increaser transmission to the steering transmissiondrives the ring gears of the secondary planetary unit in the eitherforward or reverse direction at variance of speed as well as beingcapable of braking both of the ring gears of said secondary planetaryunits.

It is therefore the object of this invention to greatly improve thespeed and torque range of a steering transmission that is particularlyadaptable for heavy vehicles.

Another object of this invention is to provide an integrated steeringand driving power system in which steering is accomplished by changingthe relative speeds of traction devices on opposite sides of thevehicle.

BRIEF DESCRIPTION OF THE DRAWING Further objects, features andadvantages of the present invention will become more clear from thefollowing detailed description of the preferred embodiment shown in theaccompanying drawings which are illustrative only and are not intendedto be limiting on the claims presented. The detailed description istaken in connection with the several views of the drawings in which:

FIG. 1 is a cross-sectional view of the transmission arrangement of thepower system of this invention;

FIG. 2 is a cross-sectional view of a variable pump unit used in thepower transmission; and

FIG. 3 is a schematic drawing for a hydraulic-servo controller adaptedto provide the control functions in an integrated steering and drivingpower system according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The transmission of the presentinvention has power applied to shaft 1 of the speed increasertransmission 2, which speed increaser transmission drives the steeringtransmission 3 to develop the proper speed and torque for the rightoutput shaft 4 and the left output shaft 5 for properly manipulating theright and left track or tread of the vehicle. Since both of thesetransmissions include reversible motor and pump units, it is consideredexpedient to first describe these units.

As shown in FIG. 2, the pump unit includes a rotatable cylinder block 6having a plurality of piston bores 7 axially positioned and openingoutwardly from the periphery thereof and housing ball pistons 8. Whenthe cylinder block is rotated, the ball pistons 8 are driven outwardlyby centrifugal force and up against the ball pump race 9, the ball pumprace being pivoted to the housing 11 by the pivot 10. It will be seenthat as the cylinder block rotates and the balls are driven against theball pump race, which draws fluid into channel 13, said balls will beforced inwardly at the right position of rotation by the eccentricity ofthe race 9 and thereby compress fluid in the cylinders which is forcedinto channel 12 formed in the pintle 14 about which the cylinder blocks6 rotate. A motor unit is constructed similar to the pump unit andchannels 12 and 13 extend over to similar channels in the motor unit.Due to the similarity of the units they can be either operated as a pumpunit or as a motor unit. It will be seen that by varying theeccentricities of the ball pump race 9 the distance which the balls movewithing their cylinders will vary and thus create varying flow by thepump unit to the motor unit and in this way the pump unit will vary thespeed of the motor unit. To vary the eccentricity of the ball pump race9, suitable means have been provided such as the fluid motor 15connected to rod 17 journaled at 16 to the ball pump race 9 and suitablycontrolled by valve means 19. The infinitely variable action of thepump-motor unit is governed by the eccentricity of the ball pump race 9and also by its capability of movement in a clockwise direction or in acounterclockwise direction in view of the two independent channels 12and 13. For further understanding operation of the reversible ball pumpand motor units, attention is called to the U.S. Pat. to Lewis, No.3,368,425, dated Feb. 13, 1968.

Returning to the speed increaser transmission 2, power input is directedto shaft 1 which drives the integrally connected support 19 for the pumpcylinder block 6 that drives the ball pistons 8 under the control of theball pump race 9, as previously described. Fluid from the pump unit istransmitted to the motor block 20 and actuates the balls 21 as governedby the ball pump race 22 and thereby rotates the ring gear 23 which isconnected to the motor block 20. Power shaft 1 extends over and drivesthe sun gear 24 which, in connection with the ring gear 23, controls themovement of the planet gears 25 and thereby the planet gear support 26and shaft 27. Thus far, it is seen that the speed of the planet gears 25is governed by the speed of rotation of the shaft 1 and the speed ofrotation either in the forward or backward direction of the ring gear23. Shaft 27 has a gear drive 28 to the steering transmission and also abrake 29, whereas power shaft 1 also has a gear drive 30 to the steeringtransmission.

Gear 30 drives gear 31 which drives gear 32 and thereby the right pumpunit 33 and left pump unit 34 which units transmit, respectively, fluidthat drives the right motor unit 35 and left motor unit 36 to drive thering gears respectively of the right planetary gearing 37 and the leftplanetary gearing 38. The gear 32 also drives shaft 39 which extends tothe right and drives the sun gear 40 of the first right planetarygearing 37 and extends to the left to drive the sun gear 41 of the firstleft planetary gearing 38. It will be seen that the speed of the planetgears 42 of the right first planetary gearing 37 is governed by thespeed of the ring gear driven by motor 35 and the speed of the sun geardriven directly by the power input shaft 1, whereas the speed of theplanet gears 43 is governed by the speed of the ring gear 38 as governedby the motor 36 and by the speed of the sun gear as driven by the powerinput shaft 1. The planet gears 42 drive the planet gear support whichis integral with the sun gear 44 of the right second planetary gearingto drive the planet gears 45 around the ring gear 46; whereas the planetgear support 47 for the planet gears 45 drive the output shaft 4. Thespeed of the planet gears 45 is controlled by the sun gear 44 and thering gear 46. Similarly, the planet gear support for the planet gears 43drives the sun gear 49 of the left second planetary gearing which drivesthe planet gears 48 around the ring gear 50 to control the speed of theplanet gear support 51 which drives the left output shaft 5. Gear 28,which is either braked by the brake 29 or driven forwardly or reverselyby the pump-motor unit of the speed increaser transmission, drives gear52 which is mounted on a shaft 53 that extends over to drive the gear54, gear 54 driving gear 55 that drives the ring gear 46 of the rightsecondary planetary gearing, whereas gear 52 drives the gear 56 thatdrives the ring gear 50 of the left secondary planetary gearing.

When gear 28 is braked, gear 52, shaft 53 and gear 54 are braked therebyholding the ring gears of the secondary right and left planetary gearingstationary, and, under this condition, the right secondary planet gears45 and left planet gears 48 rotate around their respective ring gears tocreate a slow speed and high torque multiplication to the output shafts4 and 5. On the other hand, gear 28 may be rotated either forwardly orreversely at infinitely variable speeds and correspondingly rotate thering gears of the secondary planetary gearing which, in connection withthe motor and pump units and the intervening first planetary gearing ofthe steering transmission can vary the speed of the output shafts 4 andover a wide range as desired. It will be seen that the power input shaftI constantly drives the pump unit of the speed increaser transmissionwhich, due to the eccentric control of the ball pump race thereof, canvary the drive to the motor unit and therefore the drive to the firstplanetary gearing and from there to the second planetary gearing;whereas, gear 28 can drive or hold stationary the ring gears of thesecond planetary gearing. Thus, by manipulating the eccentrics of thepumpmotor units and controlling the gear 28, the output shafts may beheld stationary, driven at slow speeds with high torque or driven athigh speeds with lower torque at an infinite variation of speed. Withthis compound transmission there is no gear shifting or clutch operationand therefore no shock in the power input means, in the transmission orin the vehicle itself. It will be seen that variable drive units otherthan the motor and pump units can be used in the transmission withalmost equal results and further that the transmission can be utilizedfor creating a power output for use other than in driving the steeringmechanism of a vehicle.

Further, it is apparent that other planetary gearing such as a third anda fourth planetary gearing, and so forth, can be utilized as desired;whereas units similar to the planetary gearing can be substituted.

In this compound transmission and aside from the input power, there areat least four adjustments, the three adjustments of the three pumpeccentrics and the braking or the drive to the ring gears of the rightand left end planetaries. Three more adjustments could be added, ifdesired, by providing selective adjustment of the three motor eccentricsrather than using stationary adjustments. It is obvious that there aredifferent kinds and types of drive controls for operation of thistransmission and a suitable hydraulic-servo controller whichcontinuously matches engine speed to a reference position in thecontroller established by the operator's throttle position is describedin the aforementioned U.S. Pat. No. 3,368,425. It is further apparentthat the adjustment and control of the compound transmission can becarried out in different ways. As an illustration, one manner ofoperating the compound transmission will now be explained.

START POSITION With the input power constantly applied the vehicle willbe brought to and held in stop position by properly modifying theeccentrics of the pump-motor units so that the effective speed of ringgear 23 is equal to offset the effective speed of sun gear 24 with brake29 being applied to absorb the torque load which stops shaft 27, gear28, gear 52, shaft 53 and gear 54, gears 52 and 54 and also holds theend planetary ring gears 55 and 56 stationary so that the output shafts4 and 5 are now being driven entirely by the sun gears of the endplanetary gearing. Inasmuch as the input power is being constantlyapplied, the sun gears of the first planetary set are being constantlydriven and therefore it is necessary to cancel the rotation of theplanet supports in order to stop the sun gears of second planetarygearing, and this is accomplished by modifying the eccentrics on thepump units 33 and 34 to drive the motor units and attached ring gears ofthe first planetary set so that the effective speed of the ring gears onthe planet gears of the first planetary set is equal to offset theefiective speed of the sun gears of the first planetary set, whereforethe planet gears rotate on their own axis which axes will be heldstationary and, being held stationary, will hold the sun gears of thesecond planetary set stationary so that the output shafts 4 and 5 willbe held in stop position.

START AND DRIVE With the vehicle held in stationary position as setforth above, the eccentric of the pump units 34 and 33 are now changedto increase or decrease the speed of the ring gears, depending onwhether the vehicle is to be driven forwardly or in reverse. As thespeed of the ring gears of the planetary 38 and 37 are increased in theforward direction, this will start the planet gears at the firstplanetary set to rotate about their sun gears and therefore to rotatethe sun gears of the second planetary set which will drive the planetgears of the second planetary set around the stationary ring gears atlow speed and high torque to start the output shafts into motion. At asuitable speed, brake 29 is released allowing pump 9 to drive motor 22and thereby the planetary gearing of the speed increaser transmission todrive the ring gears of the second planetary set so that the planetarygearing of the second planetary set is now being driven by the ring geardrive as well as the sun gear drive and the speeds of these drives canbe regulated in accordance with the setting of the eccentrics of thethree pump units and also could if desired, be regulated by the settingof the eccentries of the three motor units, and this, coupled with theincrease input power, can drive the vehicle at an infinite variation ofspeed. The change from stop to variations in speed and to a further stopposition is accomplished with constant input power and without any pauseor jerk in the application of the input power to the load. In a turningoperation, it is only necessary to vary the positions of the eccentricsof the two pump units of the steering transmission so that the outputshafts will run at different speeds. Reverse speed is accomplished byincreasing the ring gear speed in the opposite direction.

While a particular embodiment of a hydromechanical transmission has beenshown and described, it will be obvious that changes and modificationscan be made without departing from the spirit of the invention and thescope of the appended claims POWER SYSTEM OPERATION A suitable hydraulicservo controller of the same general type described in theaforementioned US Pat. No. 3,368,425 can be adapted for automaticcontrol of the present steering and driving power system whereby duringlow speed, high tractive effort operation, the steering transmission isisolated from the speed increaser transmission 3 by braking shaft 27 andat higher vehicle speed the shaft is released and the steeringtransmission permitted to operate so as to provide a large percentage ofthe overall speed range. Steering of the vehicle is accomplished bymeans of a conventional steering wheel which transmits a signal directlyto the controller to bias the drive ratios in the right and left handpump-motor units 33 and 34, respectively, and provide a differentialspeed to the treads or tracks on each side of the vehicle. The operatorselects an operating mode for the power system using means to generate asignal in the controller indicating the desired direction of travel forthe vehicle. With said drive signal selected, the operator generates athrottle signal in the controller representing the desired engine speed,such as by depressing an accelerator pedal, whereupon the controllercontinuously matches engine speed to a reference position established bythe operators throttle position. An error signal between engine andreference speed then automatically sets the drive ratio in thetransmission to maintain a desired horsepower output at the vehicletreads or tracks. Horsepower output at any engine speed is predeterminedfrom the horsepower, speed and fuel-consumption curves for theparticular engine employed. When the right first planetary gearing 37and the left first planetary gearing 38 reach the top limit oftheir'speed range, the brake 29 is released thereby permitting thesteering transmission to become operative and further increase theoutput speed of the compound hydrostatic transmission.

FIG. 3 is a schematic drawing for a hydraulic-servo controller adaptedto provide the above described control functions which includes means togenerate a throttle signal indicating the desired throttle setting ofthe prime mover or engine in the power system, means to generate asignal indicating a desired direction of travel of the vehicle, meansresponsive to said throttle signal and to said direction signal togenerate first and second drive ratio signals in said power system, andmeans responsive to said first and second drive ratio signals to adjustseparately the displacements of first and second pumpmotor units in saidpower system so as to vary the power and torque supplied to the tractiondevices on opposite sides of the vehicle. With reference to FIG. 3, aspeed reference or throttle input signal is furnished to a controller 60through mechanical linkage from an accelerator pedal. Depression of saidaccelerator pedal (not shown) causes clockwise rotation of anaccelerator input arm 61 in the controller which is connected to aninput shaft 62. The input shaft pulls away from stop 63 and is moved byspring 64 against the restriction of a dashpot 65 located in series withsaid spring. The purpose of said dashpot is to reduce the systemtransients which could result if the vehicle operator tramped" theaccelerator pedal down or suddenly released it. Countermovement of theinput shaft 62 back to the idle position is accomplished by an externalaccelerator pedal spring (not shown). Motion of the input shaft istransmitted on one end of sunning bar member 66 opposite to that whichreceives a speed sensing signal as hereinafter described. A speedsensing signal is generated in the controller by operation of spoolvalve member 67. A fluid pressure connection 68 to the controller allowshydraulic fluid from an external positive displacement pump (not shown)having an output flow proportional to prime mover engine speed to entercylinder 69. Increased flow of the hydraulic fluid increases thepressure upon spool valve 67 causing it to move against the force of areference spring 70 and apply output motion to the end of summing bar 66opposite the end receiving the throttle input signal. Pilot piston 71receives two signals through the summing bar, one proportional tointended engine speed (throttle input signal from the accelerator pedalposition) and one proportional to actual engine speed. The differencebetween these two signals or the speed-error signal, operates through aconnecting lever 67 to position the pilot piston. Pressurized oil fromthe transmission enters controller 60 through connection 72 and isported through the small end of a power piston 73 to the pilot piston 71by the path shown in the schematic drawing. Power piston 73 is adifferential area piston with the small end always subjected to thetransmission oil pressure. As also apparent from the porting path shownin said schematic drawing, the pilot piston either ports oil to or ventsoil from the large end of said power piston. Porting oil to the largeend of the power piston moves the piston to the right whereas ventingthe large end of said piston moves the piston to the left. In theabsence of a speed-error signal, the pilot piston blocks oil flow toboth said ends of the power piston and there will be no change of driveratio in the compound hydrostatic transmission. When the acceleratorpedal is depressed, however, to call for increased engine speed thesumming bar moves the pilot piston to the right and ports oil to thelarge end of the power piston, moving it to the right and momentarilyincreasing transmission ratio. With increased transmission and increasedthrottle opening, the engine speed increases which causes spool valve 67to move to the left and move pilot piston 71 in the same direction. Asthe pilot piston moves to the left it first blocks flow of oil to theleft side of the power piston thus halting any increase of transmissionratio. As the pilot piston moves further to the left, the large end ofthe power piston is vented allowing it to move to the left and decreasetransmission ratio. Assuming that vehicle power requirements have notchanged, the transmission will stabilize with an increased engine andvehicle speed and a decreased transmission ratio.

The controller power piston imparts a linear motion dependent uponengine speed and accelerator pedal position to a control plate member74. The function of said control plate is to provide a simple linearrelationship between controller output and the plurality of actuatingvalve means 19 which establish the drive ratio in each of the threevariable hydrostatic units in the compound transmission. Said controlplate can be disposed intermediate the controller and said hydrostaticunits to synchronize movement of the actuating valve means 19 for eachunit by means of cam elements 75-77 which cooperate with individualcontrol rods leading to each unit. Specifically, the cam element 75regulates movement of any output control rod 78 which is connected tosteering arm member 79 by spring-loaded linkage for actuating valvemeans 19 in pump units 33 and 34 of steering transmission 3. Incorresponding fashion, cam 76 cooperates with output control rod 80 toactuate valve means 19 in pump unit 9 of speed increaser transmission 2.Cam 77 regulates movement of output control rod 81 to operate hydraulicvalve means (not shown) which actuate brake member 29 in the speedincreaser transmission. Since all combinations of speed and directionare included in the cam rotation of said control plate, a driveselection means 82 is provided to the controller which enables theoperator to select forward, neutral or reverse ranges. For

illustrative purposes in this embodiment, six input selections have beendesignated which are high speed reverse (WR), reverse (R), neutral (N),forward (F), push-start (PS) and tow (T). The linear output of powerpiston 73 is converted into a direction and magnitude depending upon theposition of a range control link 83 in the controller. In either forwardor reverse ranges, the compound hydrostatic transmission will always bein neutral as long as the power piston is completely to the right. Ifrange selector 84 which is manually controlled by the operator is inforward, stroking of the power piston will cause the cam surface 85 tomove resulting in the controller output moving from N to F. Similarly,if reverse or high-speed reverse is selected, the controller output willmove between N and R or WR. In neutral and push-start, the cam lobe 85on range link 83 operates a bypass piston 86 located between powerpiston 73 and pilot piston 71. In neutral, the power piston ishydraulically held to the right and is unaffected by accelerator pedalposition or engine speed. Similarly, in pushstart, the power piston isheld to the left and the transmission ratio is reduced to its minimumvalue for starting. In straight forward or reverse operation, steeringarm 79 moves back and forth to actuate pump units 33 and 34 equally assignaled by the controller and the control plate output. When theoperator turns the steering wheel, however, a steer signal is given tothe control plate. This causes the steering arm to pivot and impart morestroke to one of the actuating valve means 19 than to the other whichvaries drive ratios at opposite sides of the vehicle. At low vehiclespeeds it becomes possible to insert a steering signal large enough tocause one traction device to reverse direction relative to the othertraction device. In so doing, the vehicle can execute a pivot turn aboutthe vertical vehicle axis.

While a particular embodiment of a hydromechanical transmission has beenshown and described along with its mode of operation in a power trainsystem, it will be obvious that changes and modifications can be made insaid system without departing from the spirit of the invention and thescope of the appended claims.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. A compound transmission including a first transmission having acontrollable input power and a controllable infinitely variable andreversable output power and a second transmission having controllableright and left infinitely variable and reversable power means and rightand left gears driven by said output power, right and left planetarygearing, means driving the sun gears by said right and left gearscontrollably modified by said right and left power means, means drivingthe ring gears by said infinitely variable and reversable output powerand right and left planet gears connected to drive right and left outputshafts, respectively.

2. A transmission including a drive means, an infinitely variable andcontrollable transmission connected to said drive means, planetarygearing connected to said infinitely variable and controllabletransmission, output means driven by said planetary gearing, and meansselectively braking the ring gear of said planetary gearing or fordriving said ring gear at controllable infinitely variable speeds.

3. A transmission as set forth in claim 2 wherein said infinitelyvariable and controllable transmission includes a fluid pump and motorunits, said pump and motor being connected by closed fluid circuits,said pump and motor being reversible and at least said pump having meansfor varying the displacement of fluid to said motor.

4. A transmission as set forth in claim 3, wherein said planetarygearing includes: a first planetary gearing having a sun gear connectedto said drive means and its ring gear connected to be driven by a motorunit, and a second planetary gearing having its sun gear driven by theplanet gears of said first planetary gearing and the planet gears ofsaid second planetary gearing driving said output means, and said meansfor braking or driving said ring gear driving the ring gear of saidsecond planetary gearing.

5. A transmission as set forth in claim 4, wherein the means for drivingsaid ring gear at controllable speeds, includes an infinitely variableand controllable pump and motor unit connected to said drive means.

6. A compound transmission including a that transmission having an inputshaft and a controllable infinitely variable output shaft, and a secondtransmission having a dual drive from said first transmission withcontrollable infinitely variable transmission means between said dualdrive, controlling an output means, one of said drives connected to saidinput shaft, and the other of said drives connected to said infinitelyvariable output shaft.

7. A compound transmission as set forth in claim 6, wherein thecontrollable and infinitely variable means of said first transmissionand of said second transmission include; flow circuit connected fluidpump and motor units, at least said pump unit being controllable to varyits displacement of fluid to its motor unit.

8. A compound transmission as set forth in claim 7, wherein saidinfinitely variable transmission means of said second transmissionfurther includes, a first planetary gearing having its sun gear drivenby said one drive from said input shaft and its ring gear driven by amotor unit, and a second planetary transmission having its sun geardriven by the planet gears of said first planetary gearing and its ringgear driven by the other of said drives of said first transmission, andoutput means driven by the planet gears of said second planetarygearing.

9. A compound transmission including, a first transmission including apower input shaft and an output shaft driven from said input shaftthrough the medium of controllable speed and torque variance means, saidoutput shaft being capable of being braked without stopping said inputshaft, and

a second transmission having an input shaft and an output shaft drivenfrom said input shaft through the medium of controllable speed andtorque variance means operated by the interconnection of variablemovable parts,

a means driving certain of said parts by said input shaft of the firsttransmission, and means driving the other of said parts by the outputshaft of said first transmission.

10. A transmission including, a power input; a shaft driven by saidpower input, and having right and left sun gears; right and left meansconnected to said shaft and controllable as to speed and torque forinfinitely variable output; right and left ring gears connected to bedriven by said infinitely variable output; right and left planet gearscooperating with said right and left ring gears and said right and leftsun gears to form a first set of planetary gearing; a second set ofright and left planetary gearing having their sun gears, respectively,driven by the planet gears of said right and left planet gears of saidfirst set of planetary gearing; right and left planet gear supports forthe planet gears of said second set of planetary gearing; means forconnecting said planet gearing support to right and left output shafts,and ring gears for said second set of planetary gearing.

11. A transmission as set forth in claim 10, including means driven bysaid power input controllable as to speed and torque, and meansconnecting said controllable means for driving said ring gears of saidsecond planetary gearing.

12. A transmission as set forth in claim 11, including means forselectively braking said connecting means to hold the ring gears of saidsecond planetary gearing stationary.

13. A compound transmission particularly useful for steering vehiclesincluding, a speed increaser transmission, a steering transmissionincluding end planetary gearing, the sun gears of said end planetarygearing being driven by one source form the speed increasertransmission, the ring gears of said end planetary gearing beingselectively capable of being braked or being driven by another sourcefrom the speed increaser transmission, the planet gears of said endplanetary gearing being connected to output shafts, and the steeringtransmission in between the end planetaries having infinitely variableand controllable means connected to modify the drive from one of saidsources and being capable of driving the end planetaries at the samespeed or at different speeds for a turning operation.

14. A vehicle transmission including, a first transmission having aninput shaft, infinitely variable and controllable pump and motor unitsconnected to be driven by said input shaft, said pump and motor unitsbeing interconnected by closed fluid circuits, a planetary gearinghaving its sun gear connected to be driven by said input shaft, its ringgear connected to be driven by said motor unit, and a control shaftconnected to be driven by the planet gears of said planetary gearing anda second transmission having a drive shaft, right and left sun gearsdriven by said input shaft, right and left infinitely variable andcontrollable pump and motor units driven by said input shaft, each pumpand motor unit being interconnected by a closed fluid circuit, a rightand left ring gear respectively connected to the right and left motorunit, planet gears cooperating with said right and left sun gears andsaid right and left ring gears to form afirst right and left planetarygearing, a second right and left planetary gearing having its sun gearsrespectively driven by the planet gears of said right and left firstplanetary gearing, right and left ring gears driven by said controlshaft, and planet gears for said second planetary gearing and connectedto right and left output shaft.

15. A vehicle transmission as set forth in claim 13, including a brakefor selectively stopping said control shaft.

* l l i

1. A compound transmission including a first transmission having acontrollable input power and a controllable infinitely variable andreversable output power and a second transmission having controllableright and left infinitely variable and reversable power means and rightand left gears driven by said output power, right and left planetarygearing, means driving the sun gears by said right and left gearscontrollably modified by said right and left power means, means drivingthe ring gears by said infinitely variable and reversable output powerand right and left planet gears connected to drive right and left outputshafts, respectively.
 2. A transmission including a drive means, aninfinitely variable and controllable transmission connected to saiddrive means, planetary gearing connected to said infinitely variable andcontrollable transmission, output means driven by said planetarygearing, and means selectively braking the ring gear of said planetarygearing or for driving said ring gear at controllable infinitelyvariable speeds.
 3. A transmission as set forth in claim 2 wherein saidinfinitely variable and controllable transmission includes a fluid pumpand motor units, said pump and motor being connected by closed fluidcircuits, said pump and motor being reversible and at least said pumphaving means for varying the displacement of fluid to said motor.
 4. Atransmission as set forth in claim 3, wherein said planetary gearingincludes: a first planetary gearing having a sun gear connected to saiddrive means and its ring gear connected to be driven by a motor unit,and a second planetary gearing having its sun gear driven by the planetgears of said first planetary gearing and the planet gears of saidsecond planetary gearing driving said output means, and said means forbraking or driving said ring gear driving the ring gear of said secondplanetary gearing.
 5. A transmission as set forth in claim 4, whereinthe means for driving said ring gear at controllable speeds, includes aninfinitely variable and controllable pump and motor unit connected tosaid drive means.
 6. A compound transmission including a firsttransmission having an input shaft and a controllable infinitelyvariable output shaft, and a second transmission having a dual drivefrom said first transmission with controllable infinitely variabletransmission means between said dual drive, controlling an output means,one of said drives connected to said input shaft, and the other of saiddrives connected to said infinitely variable output shaft.
 7. A compoundtransmission as set forth in claim 6, wherein the controllable andinfinitely variable means of said first transmission and of said secondtransmission include; flow circuit connected fluid pump and motor units,at least said pump unit being controllable to vary its displacement offluid to its motor unit.
 8. A compound transmission as set forth inclaim 7, wherein said infinitely variAble transmission means of saidsecond transmission further includes, a first planetary gearing havingits sun gear driven by said one drive from said input shaft and its ringgear driven by a motor unit, and a second planetary transmission havingits sun gear driven by the planet gears of said first planetary gearingand its ring gear driven by the other of said drives of said firsttransmission, and output means driven by the planet gears of said secondplanetary gearing.
 9. A compound transmission including, a firsttransmission including a power input shaft and an output shaft drivenfrom said input shaft through the medium of controllable speed andtorque variance means, said output shaft being capable of being brakedwithout stopping said input shaft, and a second transmission having aninput shaft and an output shaft driven from said input shaft through themedium of controllable speed and torque variance means operated by theinterconnection of variable movable parts, a means driving certain ofsaid parts by said input shaft of the first transmission, and meansdriving the other of said parts by the output shaft of said firsttransmission.
 10. A transmission including, a power input; a shaftdriven by said power input, and having right and left sun gears; rightand left means connected to said shaft and controllable as to speed andtorque for infinitely variable output; right and left ring gearsconnected to be driven by said infinitely variable output; right andleft planet gears cooperating with said right and left ring gears andsaid right and left sun gears to form a first set of planetary gearing;a second set of right and left planetary gearing having their sun gears,respectively, driven by the planet gears of said right and left planetgears of said first set of planetary gearing; right and left planet gearsupports for the planet gears of said second set of planetary gearing;means for connecting said planet gearing support to right and leftoutput shafts, and ring gears for said second set of planetary gearing.11. A transmission as set forth in claim 10, including means driven bysaid power input controllable as to speed and torque, and meansconnecting said controllable means for driving said ring gears of saidsecond planetary gearing.
 12. A transmission as set forth in claim 11,including means for selectively braking said connecting means to holdthe ring gears of said second planetary gearing stationary.
 13. Acompound transmission particularly useful for steering vehiclesincluding, a speed increaser transmission, a steering transmissionincluding end planetary gearing, the sun gears of said end planetarygearing being driven by one source form the speed increasertransmission, the ring gears of said end planetary gearing beingselectively capable of being braked or being driven by another sourcefrom the speed increaser transmission, the planet gears of said endplanetary gearing being connected to output shafts, and the steeringtransmission in between the end planetaries having infinitely variableand controllable means connected to modify the drive from one of saidsources and being capable of driving the end planetaries at the samespeed or at different speeds for a turning operation.
 14. A vehicletransmission including, a first transmission having an input shaft,infinitely variable and controllable pump and motor units connected tobe driven by said input shaft, said pump and motor units beinginterconnected by closed fluid circuits, a planetary gearing having itssun gear connected to be driven by said input shaft, its ring gearconnected to be driven by said motor unit, and a control shaft connectedto be driven by the planet gears of said planetary gearing and a secondtransmission having a drive shaft, right and left sun gears driven bysaid input shaft, right and left infinitely variable and controllablepump and motor units driven by said input shaft, each pump and motorunit being interconnected by a closed fluid cIrcuit, a right and leftring gear respectively connected to the right and left motor unit,planet gears cooperating with said right and left sun gears and saidright and left ring gears to form a first right and left planetarygearing, a second right and left planetary gearing having its sun gearsrespectively driven by the planet gears of said right and left firstplanetary gearing, right and left ring gears driven by said controlshaft, and planet gears for said second planetary gearing and connectedto right and left output shaft.
 15. A vehicle transmission as set forthin claim 13, including a brake for selectively stopping said controlshaft.